Nu-vinyl phosphoramidothioates and method for preparing same



United States Patent Oilfice 3,113,958 Patented Dec. 10, 1963 This invention relates to phosphoramidothioates and to processes for their preparation. More particularly, the invention relates to N-vinyl phosphoramidothioates and has for its principal objects the preparation of N-vinyl phosphoramidothioates and their use as the active components in insecticidal compositions.

The N-vinyl phosphoramidothioate's of the present invention can be represented by the general formula:

where R is hydrogen, lower alkyl or monoaryl, R is hydrogen or halogen, such as chloro, bromo or iodo, R is lower alkyl or alkoxy and R is lower alkyl. The N- vinyl phosphoramidothioa-tes hereinabove defined find utility in insecticidal compositions.

Advantageously, the N-vinyl phosphoramidothioates can be conveniently prepared by reacting substantially equimolar proportions of a phosphoramidothioate and a ,B-halogen vinyl ketone or ester in the presence of a strong base, such as an alkali metal lalkoxide, at temperatures ranging from ordinary room temperature 'to as high as 80 C.

The phosphoramidothioate reactant contemplated herein is represented by the formula:

where R, and R have the same values as above.

Illustrative phosphoramidothioates are:

0,0-diethyl N-phenyl phosphoramidothioate, O,O'-diethyl N-methyl phosphoramidothioate, 0,0-dimethyl N-ethyl phosphoramidothiate, 0,0-diisopropy-l N-tolyl phosphoramidothioate, 0,0adiethyl phosphoramidothioate, and 0,0-di-n-butyl-N-isopropyl phosphoramidothioate.

isomers and homologs of the same.

As stated previously, the reaction between the phosphosphoramidothioate and the fl-halo vinyl carbonyl compound is carried out in the presence of a strong base. Contemplated strong bases are: allcali metal alkoxides containing at least two carbon atoms, such as sodium ethoxide, potassium ethoxide and potassium tert. butoxide. Advantageously, the strong base is dissolved in an inert polar organic solvent, such as t-butanol, dirnethyl formamide or dimethoxy ethane. Sufiicient strong base, usually about one mol of the base per mol of reactant, is added to form the anion of the corresponding phosphoramidothioate.

In order to facilitate a further understanding of the invention, the following examples are presented primarily for the purpose of illustrating certain more specific details thereof. The scope of the invention is not to be deemed limited thereby except as defined in the claims. Unless otherwise stated, the parts are by weight.

EXAMPLE 1 Preparation 0 Ethyl 2-Chl0r0 S-(N-Phenyl) 0,0- Diethyl Phosphorothioamidyl Acryi'aze To a suitable reaction vessel containing a solution of 0,0-diethyl N-phenyl phosphoramidothioate (9.80 parts) in 10 parts of dirnethyl formamide is added a solution of potassium t-butoxide (5.37 parts) in parts of dimethyl formamide. Ethyl 2,3-dichloroacry1ate (8.11 parts) is added and the solution is stirred for thirty minutes. Methylene chloride (150 parts) is then added and the solution is washed several times with water and dried over magnesium sulfate.

Evaporation of the solvent leaves 14.2 parts, or 73 percent, of a crude brown product. The latter is next purified by vapor phase chromatography on. neutral alumina to obtain a yellow liquid. On analysis, the following is obtained in percent for the latter pure ethyl 2-chloro 3-(N-phenyl) 0,0-diethyl phosphorothioamidyl acrylate liquid:

Calculated: C, 47.68; H, 5.60; N, 3.71; S, 8.49; P, 8.20; Cl, 9.38. Found: C, 47.56; H, 5.82; N, 3.92; S, 8.50; P, 8.16; Cl, 9.34.

EXAMPLE 2 Preparation of Methyl (B-[QO-Diethyl .N-Methyl Phosphorothioamidyfl) Vinyl Ketone A solution of 0,0-diethyl N-methyl phosphoramidothioate (7.70 parts) in dirnethyl formamide (10 parts) is added to a solution of potassium t-butoxide (5.60 parts) in 150 parts of dimethyl formamide. A solution of methyl B-chloro vinyl ketone (5.27 parts) in 10* parts of dimethyl formamide is next added. After stirring for onehalf hour, methylene chloride (150 parts) is added, and the solution is washed several times with Water and dried over magnesium sulfate. The latter is filtered off, the solvent evaporated, and the product distilled at 10p. pressure to yield about 31 percent of methyl (,8-[0,0-diethyl N- methyl phosphorothioamidyl] vinyl ketone having a boiling point between 112 C. and 113 C. The product is further purified by chromatography on alumina to obtain a yellow liquid. On analysis, the following data is found:

Calculated for PSNO C H .C, 43.01; H, 7.22; N; 5.57; S, 12.76; P, 12.32. Found; C, 43.19; H, 7.15; N, 5.69; S,'12.71; P, 12.29.

EXAMPLE 3 Preparation of Ethyl Z-Chloro' 3-(N-Methyl) O,O-Diethyl Phosphorothioamidyl Acrylate In a suitable reaction vessel containing a solution 'of 0,0-diethyl N-methyl phosphoramidothioate (3.15 parts) in dimethyl formamide (10 parts) is added a solution of potassium t-butoxide (2.32 parts) in dirnethyl formamide (150 parts). Ethyl 2,3-dicl1loroacrylate (3.50 parts) is added and the solution is stirred for thirty minutes. Methylene chloride (150 parts) is next added. Resultant solution is washed several times with water and dried over magnesium sulfate. Filtration of the latter and evaporation of the solvent leaves 4.9 parts of crude ethyl 2-chloro 3-(N-methyl) 0,0-diethyl phosphorothioamidyl acrylate.

, chloride.

A product is distilled at 20 pressure. following data is obtained for PSNClO' C H Calculated-C, 35.83; H, 5.68; N, 4.64; S, 10.63; Cl,

. v.9 The product is purified by chromatography on neutral alumina. On analysis, the following data is recorded:

Calculated for PNSO ClC H .-C, 40.07; H, 6.39; N, 4.67; S, 10.70; P, 11,83; Cl, 10.33. Found: C, 39.80; H, 6.89; N, 4.63; S, 10.61; P, 11.84; Cl, 10.21.

7 EXAMPLE 4 Preparation of Ethyl Z-Chloro 0,0-Diethyl Phosphorothioamidyl Acrylate To a suitable reaction vessel containing 0,0-diethyl phosphoramidothioate (1014 parts) in dimethyl formam- "ide parts, by volume) is added a solution of potassium t-butoxide (7.72 parts) in 50 parts of dinethyl formamide.

Ethyl a,,B-dichloroacrylate (5.07 parts) in dimethyl formamide (10 parts) is added. After fifteen minutes, potassium t-butoxide (6.72 parts) is added followed by 50 parts by volume of dimethyl formamide and then 5.07 parts of ethyl 2,3-dichl0roacrylate in 10 parts of dimethyl formamide. After stirring for one hour, 150 parts ofmethylene chloride are added. Resultant solution is washed twice with water. Aqueous washings are acidfied with dilute hydrochloric acid and extracted with methylene magnesium sulfateand evaporated to yield 3.8 parts or 21 percent of brown liquid which is shown by vapor phase chromatography analysis to be 91 percent pure ethyl 2-- chloro 0,0-diethyl phosphorothioamidyl acrylate. The Upon analysis, the

11.75; P, 10.26. Found: C, 35.99; H, 5.90; N, 4.86; S, 10.88; Cl, 11.83; P, 10.27. I

EXAMPLE 5 To illustrate the insecticidal activity of the compounds of the subject invention, the following tests are run and the results recorded in-Table 1 below:

The compounds to be tested are made up as 0.1% solutions in 65% acetone/ water. Three inch pots con-.

taining two or three Nasturtium plants two inches tall are infested two days before they are selected for testing. The pots are placed on a turntable maintained at four revolutions per minutes and sprayed for two revolutions The methylene chloride solution is dried over I 4 We claim:

1. Compounds represented by the formula:

where R is a radical selected from the group consisting of hydrogen, lower valkyl, phenyl and lower alkyl substituted phenyl, R is a radical selected from the group consisting of hydrogen and halogen, R is a radical selected from the group consisting of lower alkyl and lower alkoxy, and R stands for lower alkyl.

2. The compound: ethyl Z-chloro 3-(N-phenyl) 0,0- diethyl phosphorothioamidyl acrylate.

3. .The compound: ethyl 2-chloro 3-(N-eth'yl) 0,0-diethyl phosphorothioamidyl 'arcrylate.

4. The compound: ethyl 2-chloro (LO-diethyl phosphorothioamidyl acrylate.

5. The compound: methyl(;3- [0,0-diethyl .N-methyl phosphorothioamidyfl) vinyl ketone.

6. The process for preparing a N-vinyl phosphoramidothioate of the formula:

with a #15 De Vilbiss Atomizer at twenty pounds per 7 'square inch air pressure. The spray tip is held about. six

inches from the plants and the spray is directed so as to give complete coverage of the aphids and the plants. The sprayed plants are laid on their side on white enamel trays (9%" x 13%" x A) which have had the edges coated with No. S.A.E. oil as a barrier. Mortality counts are made after holding for two days at F. and the results jin percent are recorded in Table I below:

I TABLE I.APHIDS TEST Compound: Percent kill Methyl ([3-[0,0-diethyl N-methyl phosporothioamidyl] vinyle ketone Ethyl 2-chloro 3-(N-phenyl) 0,0-diethyl phosphorothioamidyl acrylate 98 Ethyl Z-chloro 3-(N-methyl 0,0, diethyl phosphorothioamidyl arcrylate 100 Ethyl 2-chloro 0,0-diethyl phosphorothioamidyl acrylate 98 Where R is a radical selected from the group consisting of hydrogen, lower alkyl, phenyl and lower alkyl substituted phenyl, R is a radical selected from the group consisting of hydrogen and halogen, R is a radical selected from the group consisting of lower alkyl and lower alkoxy, and R stands for lower alkyl, which comprises the steps of: bringing into reactive combination in substantially equirnolar quantities a phosphoramidothioate reactant of the formula:

and a ,G-halo vinyl carbonyl compound having the for mula: a

ate reactant is 0,0,-diethyl N-methyl phosphbramidothio:

ate and the vinyl reactant is ethyl 2,3-dichloroacrylate.

10. The process according to claim 6, wherein the thioate reactant is 0,0'-methyl phosphoramidothioate and the vinyl reactant is ethyl 2,3-dichloroacrylate.

' NO. references cited. 

1. COMPOUNDS REPRESENTED BY THE FORMULA:
 6. THE PROCESS FOR PREPARING A N-VINYL PHOSPHORAMIDOTHIOATE OF THE FORMULA: 